A reassignment of molecular orbital configurations of the electronic states of ScF

Ab initio molecular orbital calculations have been performed on low-lying electronic states of ScF. The calculations suggest a reassignment of the molecular orbital configurations of the lowest lying Φ states, and suggest also that some of the low-lying Π states may not be well described by single configuration wavefunctions.     

On the description of reactions in solution

A formulation for diffusion-influenced reactions in solution is given in which reactive and translational contributions are separated, steady state rate-limiting step formulations are generalized to the dynamical case and the influence of different experimental initial conditions is isolated.     

The determination of the photoelectron escape depths in polymers and other materials

Relative inelastic mean free paths (λ) for 1000-eV electrons have been determined for a number of polymers and other materials (relative to 967-eV electrons in graphite) using X-ray photoelectron spectroscopy. The carbon-containing compounds were found to have values of λ in the range 3.7–7.1 nm while λ (silicon) was 3.0 nm i.e. 1.2–2.3 times and 1.0 times that for graphite.     

Extraction of nonstationarity information from correlation noise

A gas chromatograph is used as a model of a monitored process stream, and a method is developed to detect fixed-amplitude changes either in component concentration or system response to a perturbation. The multiple injection input and its advantages are based on the principles of correlation chromatography. The deconvolution of the aperiodic input pattern from the output results in a signal peak representing average system response and correlation “noise” which, when calibrated, gives the direction and magnitude of the change which has occurred. Because of the signal-averaging effect of the multiple inputs and deconvolution process, the effects of random fluctuations and noise are reduced.     

An NMR investigation of the existence of halide and carboxylate co‐solute effects on the rotational barrier about the C?N bonds in urea and thiourea

Rotational barriers of the NH₂ group in thiourea and benzylurea in solution become slightly larger in the presence of anionic hydrogen‐bond acceptors. The interactions between the N? H bond and different anions were investigated in acetonitrile solution using ¹H{¹⁴N} variable‐temperature NMR. Line‐shape analyses of the spectra show a weakly anion‐dependent increase in ΔG^? of rotation, with benzoate having the strongest effect and iodide the weakest. Hydrogen‐bonding acidities of benzylurea and thiourea were also measured on the Abraham solute hydrogen‐bond acidity scale by proton NMR. Copyright © 2010 John Wiley & Sons, Ltd.     

Local phase decomposition as a cause of polarization fatigue in ferroelectric thin films

We show that lead zirconate titanate thin films undergo local phase decomposition during fatigue. The original remanent polarization of the fatigued film is completely restored after furnace annealing in an O2 atmosphere, following a significant regrowth of a perovskite phase from the pyrochlorelike structure. By comparing our data with other researchers' work on annealing of fatigued ferroelectric samples, we conclude that local phase separation is the generic reason for electrical fatigue in ferroelectrics. A fatigue model is proposed in order to interpret our experimental data.